Non-destructive inspection includes a wide group of analysis techniques used in science and industry to evaluate the properties of a test structure (e.g., one or more of a material, a part, a component, a product, and/or an apparatus) without causing damage. Such techniques may be used for quality inspection, product evaluation, product development, and maintenance inspection, in particular in industries demanding high uptime and high reliability structures. For example, aerospace test structures may be subject to non-destructive inspection at the point of manufacture and during routine operation intervals. Other industries using non-destructive inspection include health care, petrochemical, power generation, and automotive industries.
Non-destructive inspection may employ a probe including an electronic emitter and/or an electronic sensor. For example, ultrasonic inspection may use an ultrasonic transducer that emits a short-duration pulse of sound and that detects returning echoes. As another example, eddy current inspection may use an inductive probe whose impedance is affected by nearby conductive materials. The typical eddy current probe emits an electromagnetic waveform and senses a distortion in the waveform. Other types of non-destructive inspection techniques include microwave and terahertz inspection (which respectively use microwave and terahertz-wave electromagnetic radiation to interrogate the state of a test structure). Probes for non-destructive inspection may be small enough to be portable and/or to be hand-held.
One problem with non-destructive techniques is that probes typically do not intrinsically know or record their location relative to the test structure. A test structure may be a fairly large structure, potentially with complicated surface geometry. As a probe passes over a region of interest to collect test data relating to that location of the test structure, the precise location of the probe is typically neither known nor repeatable.
Non-destructive inspection systems that can track the location of the probe relative to the test structure typically use a scan bridge or similar positioning device (e.g., an x-y gantry, and/or an R-theta arm) to establish the location of an attached probe. The positioning device generally is configured to move the attached probe to a known location or to record the position of the attached probe. The inclusion of a positioning device with a non-destructive inspection system results in additional equipment to store, carry, assemble, and/or calibrate. The added complexity of operating a non-destructive inspection system with a positioning device is a burden that limits the utility of such non-destructive inspection systems, for example, in field service. Hence, there is a need for non-destructive systems that are capable of tracking the probe position without the complexity of a positioning device.